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Web Based BACnet Compatible Controls Applied to Emerging HVAC Technologies

Web Based BACnet Compatible Controls Applied to Emerging HVAC Technologies. ASHRAE Orlando Seminar 8, February 6, 2005. Stanley A. Mumma, Ph.D., P.E. Prof. Architectural Engineering Penn State University @ Univ. Park sam11@psu.edu http://doas-radiant.psu.edu. Presentation Outline.

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Web Based BACnet Compatible Controls Applied to Emerging HVAC Technologies

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  1. Web Based BACnet Compatible Controls Applied to Emerging HVAC Technologies ASHRAE Orlando Seminar 8, February 6, 2005 Stanley A. Mumma, Ph.D., P.E.Prof. Architectural EngineeringPenn State University @ Univ. Parksam11@psu.eduhttp://doas-radiant.psu.edu

  2. Presentation Outline • Emerging Technologies: EW, DOAS, CRCP, Continual Performance monitoring • Practical Application • EW Control: 3 regions, w/ frost control • CRCP: condensate control • Control Logic, (Symp. paper OR-05-3-3) • Some benefits of employing Web Based Ctr’l • Some benefits of using BACnet • Conclusions and recommendations

  3. DOE Report 3 2 1 3

  4. The Technologies Integrated High Induction Diffuser 20-70% less OA, Cool/Dry Supply DOAS Unit W/ Energy Recovery Building With Sensible and Latent cooling decoupled Parallel Sen. Radiant Cooling System

  5. V3 Practical Application

  6. Practical Application Cont’d

  7. Practical Application Graphic

  8. EW Control Region 1 Region 2 Region 3

  9. CRCP Condensate Control • First Stage: keep panel inlet fluid temperature above the space DPT. • Second Stage: Use a passive fail safe condensate sensor, with a spring return temperature control valve to isolate CRCP from source of cooling, if condensate sensed. • Alt Second Stage, for buildings with movable sash: Monitor the sash position and act as appropriate.

  10. Sash Position Condensation Control

  11. The System Control Logic:Single Zone, or Multi-Zone

  12. Now the Web BasedControl Discussion

  13. Web Based • Facilitates system monitoring and control from anywhere. We could do it here if we had an internet connection. • Access to system and trend logs lead to discoveries and refinements, previously hard to realize. (an example will follow) • Can facilitate occupant participation (an example will follow).

  14. An Example Refinement:Winter Supply Air Temperature

  15. Observations • EW is operating in the on-off mode • Supply air temperature to the space varies from about 35F to 65F. Good that high induction diffusers are used. • It only takes about 20 minutes for the space temperature to drop 1F (control set to hold space temperature between 73 and 74F) • In some cases the SAT remains at OA temperature for over 3 hours.

  16. What are the Alternatives? • Modulate the EW speed to prevent on-off cycling. Capacity control in first ~5 rpm e 5 0 20 rpm

  17. V3 Operating the panel pumpin the winter with EW On-off

  18. EW on-off w/ & w/o panel pump

  19. Panel Inlet Water Temperature As The EW Cycles On-off.

  20. An Example of Occupant Participation aided by web access

  21. Now the BACnet Compatible Control Discussion

  22. BACnet Advantages, even in this very small project. • Enables web access from anyplace with an internet connection. • Performance and control available from the campus central computer system. • Enables expansion of a full control module to accommodate more inputs/outputs . • Impacts the ease and cost of installation. • May reduce mislabeled points.

  23. Web Browser Server Digital, I Cond Window t5:t14 t1, h1:t4, h4 CO2-1CO2-2 FM1:FM5 SF RF EW Ch1 Ch2 Panel P D1 V1V2V3 Router Digital, O Control Module Analog, I Analog, O Analog, I 24VPower Supply Chiller FAV

  24. What If the FAV Had a BACnet Control? • Could connect the FAV control to the BACnet MS/TP network. • Free 5 input connections and associated wire and installation • Free 4 output connections and associated wire and installation. • 15% of the input and 40% of the output connections now eliminated.

  25. Web Browser Server Digital, I Cond Window t5:t14 t1, h1:t4, h4 CO2-1CO2-2 FM1:FM5 SF RF EW Ch1 Ch2 Panel P D1 V1V2V3 FAV Router Digital, O Control Module Analog, I Analog, O Analog, I 24VPower Supply Chiller FAV

  26. What If the Chiller Had a BACnet Control? • Could connect the Chiller control to the BACnet MS/TP network. • Free 3 input connections and associated wire and installation • Free 3 output connections and associated wire and installation. • Another 12% of the input and 30% of the output connections eliminated

  27. Web Browser Server Digital, I Cond Window t5:t14 t1, h1:t4, h4 CO2-1CO2-2 FM1:FM5 SF RF EW Ch1 Ch2 Panel P D1 V1V2V3 Ch FAV Router Digital, O Control Module Analog, I Analog, O Analog, I 24VPower Supply Chiller FAV

  28. What If the Air Flow Measuring Devices were BACnet Enabled? • Could connect the 3 Air Flow Measuring Stations to the BACnet MS/TP network. • Free 5 input connections and associated wire and installation. • Another 19% of the input connections now eliminated. • If all 3 changes were implemented, 46% of the input and 70% of the output connections eliminated. And associated wire and installation.

  29. Web Browser Server Digital, I Air FM Cond Window t5:t14 t1, h1:t4, h4 CO2-1CO2-2 FM1:FM5 SF RF EW Ch1 Ch2 Panel P D1 V1V2V3 Ch FAV Router Digital, O Control Module Analog, I Analog, O Analog, I 24VPower Supply Chiller FAV

  30. Impact On Wire Pulling, Terminating & Expansion Modules!

  31. Conclusions • Control of this system employing EW, CRCP, DOAS, and Chiller was successfully achieved. • Web accessibility made a complete under-standing of the system performance possible. • Web accessibility made control logic revisions easy. • BACnet capability has the potential to reduce the installation costs if properly considered at the beginning, or • Free up input and output terminals on existing control modules, allowing expansion.

  32. QUESTIONS

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